// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_RENDERER_HOST_PEPPER_QUOTA_RESERVATION_H_
#define CONTENT_BROWSER_RENDERER_HOST_PEPPER_QUOTA_RESERVATION_H_

#include <map>

#include "base/callback.h"
#include "base/macros.h"
#include "content/common/content_export.h"
#include "ppapi/c/pp_stdint.h" // For int64_t on Windows.
#include "ppapi/shared_impl/file_growth.h"
#include "storage/browser/fileapi/file_system_context.h"
#include "url/gurl.h"

namespace storage {
class FileSystemURL;
class OpenFileHandle;
class QuotaReservation;
}

namespace content {

struct QuotaReservationDeleter;

// This class holds a QuotaReservation and manages OpenFileHandles for checking
// quota. It should be created, used, and destroyed on a FileSystemContext's
// default_file_task_runner() instance. This is a RefCountedThreadSafe object
// because it needs to be passed to the file thread and kept alive during
// potentially long-running quota operations.
class CONTENT_EXPORT QuotaReservation
    : public base::RefCountedThreadSafe<QuotaReservation,
          QuotaReservationDeleter> {
public:
    // Static method to facilitate construction on the file task runner.
    static scoped_refptr<QuotaReservation> Create(
        scoped_refptr<storage::FileSystemContext> file_system_context,
        const GURL& origin_url,
        storage::FileSystemType file_system_type);

    // Opens a file with the given id and path and returns its current size.
    int64_t OpenFile(int32_t id, const storage::FileSystemURL& url);
    // Closes the file opened by OpenFile with the given id.
    void CloseFile(int32_t id, const ppapi::FileGrowth& file_growth);
    // Refreshes the quota reservation to a new amount. A map that associates file
    // ids with maximum written offsets is provided as input. The callback will
    // receive a similar map with the updated file sizes.
    typedef base::Callback<void(int64_t, const ppapi::FileSizeMap&)>
        ReserveQuotaCallback;
    void ReserveQuota(int64_t amount,
        const ppapi::FileGrowthMap& file_growth,
        const ReserveQuotaCallback& callback);

    // Notifies underlying QuotaReservation that the associated client crashed,
    // and that the reserved quota is no longer traceable.
    void OnClientCrash();

private:
    friend class base::RefCountedThreadSafe<QuotaReservation,
        QuotaReservationDeleter>;
    friend class base::DeleteHelper<QuotaReservation>;
    friend struct QuotaReservationDeleter;
    friend class QuotaReservationTest;

    QuotaReservation(
        scoped_refptr<storage::FileSystemContext> file_system_context,
        const GURL& origin_url,
        storage::FileSystemType file_system_type);

    // For unit testing only. A QuotaReservation intended for unit testing will
    // have file_system_context_ == NULL.
    QuotaReservation(scoped_refptr<storage::QuotaReservation> quota_reservation,
        const GURL& origin_url,
        storage::FileSystemType file_system_type);

    ~QuotaReservation();

    void GotReservedQuota(const ReserveQuotaCallback& callback,
        base::File::Error error);

    void DeleteOnCorrectThread() const;

    scoped_refptr<storage::FileSystemContext> file_system_context_;
    scoped_refptr<storage::QuotaReservation> quota_reservation_;
    typedef std::map<int32_t, storage::OpenFileHandle*> FileMap;
    FileMap files_;

    DISALLOW_COPY_AND_ASSIGN(QuotaReservation);
};

struct QuotaReservationDeleter {
    static void Destruct(const QuotaReservation* quota_reservation)
    {
        quota_reservation->DeleteOnCorrectThread();
    }
};

} // namespace content

#endif // CONTENT_BROWSER_RENDERER_HOST_PEPPER_QUOTA_RESERVATION_H_
